Kidney NGAL is a novel early marker of acute injury following transplantation

Abstract

Acute kidney injury secondary to ischemia–reperfusion in renal allografts often results in delayed graft function. We tested the hypothesis that expression of neutrophil gelatinase-associated lipocalin (NGAL) is an early marker of acute kidney injury following transplantation. Sections from paraffin-embedded protocol biopsy specimens obtained at approximately one hour of reperfusion after transplantation of 13 cadaveric (CAD) and 12 living-related (LRD) renal allografts were examined by immunohistochemistry for expression of NGAL. The staining intensity was correlated with cold ischemia time, peak post-operative serum creatinine, and dialysis requirement. There were no differences between the LRD and CAD groups in age, gender or preoperative serum creatinine. Using a scoring system of 0 (no staining) to 3 (most intense staining), NGAL expression was significantly increased in CAD specimens (2.3±0.8 versus 0.8±0.7 in LRD, pR=0.87, pR=0.86, p<0.001). Four patients developed delayed graft function requiring dialysis during the first week posttransplantation; all of these patients displayed the most intense NGAL staining in their first protocol biopsies. We conclude that NGAL staining intensity in early protocol biopsies represents a novel predictive biomarker of acute kidney injury following transplantation.